Brother MFC-9320CW Service Manual page 148

■ All one color
Memo:
You can check this image defect with the function code 71.
(Refer to "1.4.21 Color test pattern (Function code 71)" in Chapter
Step Cause
1 Corona wire
failure
2
3 HVPS control PCB
failure
4 High-voltage power
supply PCB failure
5 LED ASSY failure
6 LED head control
PCB failure
7 Main PCB failure
Check
Are the electrodes on
the drum unit of the
appropriate color and
machine body dirty?
Is the corona wire
damaged?
Is the problem solved
after replacing the HVPS
control PCB ASSY?
Is the problem solved
after replacing the
high-voltage power
supply PCB ASSY?
Is the problem solved
after replacing the LED
ASSY?
Is the problem solved
after replacing the LED
head control PCB
ASSY?
Is the problem solved
after replacing the main
PCB ASSY?
3-67
7)
Remedy
Result
Yes Clean both electrodes.
(Refer to Fig. 3-3
(P3-32) and Fig. 3-6
(P3-33))
Yes Replace the drum unit.
Yes Replace the HVPS
control PCB ASSY.
Yes Replace the
high-voltage power
supply PCB ASSY.
Yes Replace the LED ASSY.
Yes Replace the LED head
control PCB ASSY.
Yes Replace the main PCB
ASSY.
Confidential